OBJECTIVE: To evaluate the efficiency of asanguinous hypothermic total body washout (TBW) in treating rabbits with endotoxin shock. Total body washout (TBW) is achieved as follows. Five hundred ml of room temperature (22 degrees C) lactated Ringer's solution is infused into the rabbit's femoral artery while blood is drained from a venous cannula over 4 minutes. Hematocrit falls below 1 percent. An intra-arterial infusion of whole blood (70 to 100 ml) with simultaneous venous drainage completes TBW. E. coli endotoxin is labeled with Cr51 C13. Cr51-labeled endotoxin (5 mg/Kg) is injected intravenously into 120 rabbits. Blood pressure, central venous pressure, arterial and venous blood gases, muscle pH and pO2, ECG, and muscle and esophageal temperatures are monitored. When the animals develop endotoxin shock (according to our criteria), they are randomized into two groups. Group 1 is a control group and group II is treated with TBW. The total amount of endotoxin removed by TBW is determined by using Cr51. The five-day survival rate of Group II is compared with that of Group I. At autopsy the tissue bound endotoxin is quantitated in both groups.